Patent
Steel with excellent delayed fracture resistance and tensile strength of 1801 MPa class or more, and its shaped article
| العنوان: | Steel with excellent delayed fracture resistance and tensile strength of 1801 MPa class or more, and its shaped article |
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| Patent Number: | 7,754,029 |
| تاريخ النشر: | July 13, 2010 |
| Appl. No: | 11/490955 |
| Application Filed: | July 21, 2006 |
| مستخلص: | Steel and steel shaped articles with an excellent delayed fracture resistance and a tensile strength of the 1600 MPa class or more, containing, by mass %, C: 0.20 to 0.60%, Si: 0.50% or less, Mn: over 0.10% to 3%, Al: 0.005 to 0.1%, Mo: over 3.0% to 10%, and, as needed, one or more of W: 0.01 to 10%, V: 0.05 to 1%, Ti: 0.01 to 1%, Nb: 0.01 to 1%, Cr: 0.10 to 2%, Ni: 0.05 to 1%, Cu: 0.05 to 0.5%, and B: 0.0003 to 0.01%, and a balance of Fe and unavoidable impurities and, further, a method of production comprising shaping the above steel to a desired shape (for example, a bolt shape), quenching it, then tempering it at 500 to 750° C. in temperature range. |
| Inventors: | Kubota, Manabu (Futtsu, JP); Yoshida, Suguru (Futtsu, JP); Tarui, Toshimi (Futtsu, JP); Matsuda, Hideki (Wako, JP); Mizuno, Koki (Wako, JP); Ohya, Tadashi (Wako, JP) |
| Assignees: | Nippon Steel Corporation (Tokyo, JP), Honda Motor Co., Ltd. (Tokyo, JP) |
| Claim: | 1. A steel with an excellent delayed fracture resistance and a tensile strength of the 1801 MPa class or more consisting essentially of, by mass %, C: 0.20 to 0.60%, Si: 0.50% or less, Mn: over 0.10% to 3%, Al: 0.005 to 0.045%, in an amount effective to deoxidize and form nitrides to make pre-austenite grains finer, Cu: 0.05 to 0.30%, in an amount effective to improve corrosion resistance, Mo: over 3.0% to 10%, and further consisting essentially of a quenched and tempered microstructure, treated by tempering at 600% to 750° C., containing fine Mo carbide precipitates, and a balance of Fe and unavoidable impurities. |
| Claim: | 2. The steel with an excellent delayed fracture resistance and a tensile strength of the 1801 MPa class or more as set forth in claim 1 , further consisting essentially of, by mass %, one or more of W: 0.01 to 10%, V: 0.05 to 1%, Ti: 0.01 to 1%, and Nb: 0.01 to 1%. |
| Claim: | 3. The steel with an excellent delayed fracture resistance and a tensile strength of the 1801 MPa class or more as set forth in claim 1 , further consisting essentially of, by mass %, one or more of Cr: 0.10 to 2%, Ni: 0.05 to 0.70%, Cu: 0.05 to 0.30%, and B: 0.0003 to 0.01%. |
| Claim: | 4. A steel, having an excellent delayed fracture resistance and a tensile strength in the 1801 MPa class or more, in accordance with claim 1 , wherein the steel is shaped to a steel shaped article by a process comprising the steps of shaping the steel to a desired shape, then quenching it, and thereafter tempering it in temperature range of 600° to 750° C. |
| Claim: | 5. A steel, having an excellent delayed fracture resistance and a tensile strength in the 1801 MPa class or more, in accordance with claim 2 , wherein the steel is shaped to a steel shaped article by a process comprising the steps of shaping the steel to a desired shape, then quenching it, and thereafter tempering it in temperature range of 600° to 750° C. |
| Claim: | 6. A steel, having an excellent delayed fracture resistance and a tensile strength in the 1801 MPa class or more, in accordance with claim 3 , wherein the steel is shaped to a steel shaped article by a process comprising the steps of shaping the steel to a desired shape, then quenching it, and thereafter tempering it in temperature range of 600° to 750° C. |
| Claim: | 7. A bolt produced from the steel in accordance with claim 1 , having an excellent delayed fracture resistance and a tensile strength in the 1801 MPa class or more. |
| Claim: | 8. A bolt produced from the steel in accordance with claim 2 , having an excellent delayed fracture resistance and a tensile strength in the 1801 MPa class or more. |
| Claim: | 9. A bolt produced from the steel in accordance with claim 3 , having an excellent delayed fracture resistance and a tensile strength in the 1801 MPa class or more. |
| Current U.S. Class: | 148/320 |
| Patent References Cited: | 1598437 November 2005 1434948 May 1976 55-2785 January 1980 64-052045 February 1989 05-148576 June 1993 05-148580 June 1993 2000328191 November 2000 2001032044 February 2001 2002-173739 June 2002 2004 231992 August 2004 |
| Other References: | Computer-generated English translation of Japanese patent 2002-173739, Hiragami et al. Jun. 21, 2002. cited by examiner Kubota, M. et al., “Development of High Tensile Strength Steel for Bolts,” equivalent to Tetsu-to-Hagane, vol. 83 (1997), p. 454. cited by other |
| Primary Examiner: | Yee, Deborah |
| Attorney, Agent or Firm: | Kenyon & Kenyon LLP |
| رقم الانضمام: | edspgr.07754029 |
| قاعدة البيانات: | USPTO Patent Grants |
| الوصف غير متاح. |